1. Field of the Invention
This invention relates to an elasticized sleeve construction suitable for orthotic and prosthetic applications.
2. Related Art
Orthotic and prosthetic elasticized sleeves are described in U.S. Pat. Nos. 4,908,037 and 5,830,237. Such sleeves are fabricated of elastic or elasticized materials and may be used to support and reinforce muscles, joints and extremities of those in need of such assistance and to provide an airtight seal between a residual limb of an amputee and an prosthesis socket worn by the amputee.
An orthotic or prosthetic sleeve is formed by joining sections of elasticized fabric shaped in tubular form and joined at their axial ends to form a tubular sleeve extending in an axial direction. The sleeve may be cylindrical or may be curved.
In accordance with one embodiment of the invention, the elasticized fabric used to make the sleeve sections exhibits different elastic stiffness (different elasticity) in the lengthwise and widthwise directions of the fabric. That is, the fabric is elastically stiffer (has less elasticity or a higher modulus of elasticity) in one direction than in a direction perpendicular to the one direction.
By joining together the fabric sections in a specified configuration, the sleeve will have at least one section having its direction of higher elastic stiffness in a direction transversely of the sleeve and at least one section having its direction of higher elastic stiffness extending along the axial direction of the sleeve.
Other stiffening elements may be provided along the length of the sleeve in accordance with known principles to provide lateral rigidity to the sleeve.
The entire inner surface of the sleeve is coated with a discrete layer of silicone elastomer that is firmly bonded to the fabric material constituting the sleeve. The silicone elastomer layer is thick enough and soft enough to be very comfortable to the user and to provide an airtight seal between the sleeve and the skin.
In a preferred embodiment, at least two elasticized fabric elements are connected together to define a tubular sleeve extending on an axis and having at least two fabric sections. The elasticized fabric constituting these sections has a higher elastic stiffness along one direction of the fabric than along an orthogonal direction relative to the said one direction. One of the at least two sections is formed so that the direction of higher stiffness of the fabric extends axially along the sleeve axis and the other section is formed so that the direction of higher stiffness extends generally transversely of the sleeve axis.
In accordance with one embodiment of the invention, at least three elasticized fabric elements are utilized to define the orthotic or prosthetic sleeve of the invention, wherein the elements are fabricated in tubular form and connected along their axial ends to define a tubular sleeve having two end sections and a middle section.
The end sections are formed so that the direction of higher elastic stiffness of the fabric extends axially along the sections and the middle section is formed so that the direction of higher elastic stiffness of the fabric extends generally transversely of the sleeve axis.
The interior surface of the sleeve is entirely coated with a continuous, cured silicone elastomer material that forms a discrete layer on the inside surface of the sleeve.
The silicon elastomer preferably has a Shore 00 of 25-70; a minimum tensile strength of 230 lbs/inch; a 100% modulus of 8 psi; a 500% modulus of 61 psi; a minimum tear strength of 49 lbs/inch; a maximum tensile strength of 500 lbs/inch; and an elongation of about 1000%.
The tubular sleeve in accordance with one embodiment may be provided with a curvature along a portion of its length and wherein the section having its direction of higher stiffness extending generally transversely of the sleeve axis is located along the curvature.
In a preferred embodiment, stiffening ribs are provided extending lengthwise of the sleeve on diametrically opposite sides thereof, the stiffening ribs being formed of relative inelastic material, for example a relatively inelastic fabric.